The implementation is, if you enable this option when making a pull request, people with write access to the target project also get write access to your branch, so they can grab it, make some fixes, git commit (perhaps with --amend), git push -f to your fork, and then merge it from your pull request, and you keep authorship and the pull request gets resolved like normal.

For what it's worth, the Linux kernel community has a process for this too - a subsystem maintainer can absolutely grab someone's patch and git commit --amend. Usually it's considered courteous to add a "[[email protected]: fixed style]" line at the bottom of the commit message. I'm a little surprised the maintainer didn't do that in this case but I bet life got in their way too :)